NASHVILLE, Tenn., March 5 (Reuters) - A Tennessee man was charged on Wednesday with murder and aggravated kidnapping in the death of a nursing student who disappeared three years ago from the driveway of her rural home.

Zachary Rye Adams, 29, was arrested last week on an unrelated aggravated assault charge and is being held without bond in the Chester County Jail, authorities said at a news conference.

Victim Holly Bobo, a cousin of country singer Whitney Duncan, was last seen on April 13, 2011 by her brother. He told authorities he saw a man in hunting garb leading the petite 20-year-old blonde woman away from the family home in Darden, about 90 miles southwest of Nashville.

Bobo had been preparing to go to class at nursing school on the morning of her disappearance.

Some spectators at the news conference at the Decatur County courthouse responded with gasps and sobs when Tennessee Bureau of Investigation director Mark Gwyn announced the murder charge.

The tightly knit, rural community has been holding regular vigils and keeping up hopes that Bobo would be found alive.

The search for Bobo and her abductor or killer was the most exhaustive in terms of staff hours and expense that state law enforcement has ever undertaken, Gwyn said.

Authorities deflected questions about whether they had located her remains or if there would be more arrests.

"It's taken us three years to get to this point," Gwyn said. "We can't mess it up now."

Tennessee District Attorney General Hansel McAdams said he could seek the death penalty against Adams.

McAdams said authorities believe they can prove Bobo was taken from her home forcefully and killed.

Bobo's disappearance gained national attention as volunteers and law enforcement searched the countryside for weeks.

Authorities executed search warrants last Friday in the county. Among the locations searched was Adams' home in Holladay, Tennessee, about 16 miles from Bobo's home. (Reporting by Tim Ghianni; Editing by Mary Wisniewski, Ellen Wulfhorst and Cynthia Osterman)